Numerous types of road sign exist for performing this function, they may be made of metal or of plastic and they are stood on the ground by means of an appropriate stand providing a stand area or "footprint" which is large enough to ensure that the road sign is stable. The need to have a large footprint gives rise to devices that are relatively bulky and which are difficult to store and to transport. In addition, it is often essential to ballast the bases of such devices or to reinforce their stability on the ground some other way by such means as happen to be available on the worksite about which warning is to be given. Such means (wedges, stones, heavy objects, . . . ) are never adapted to securing such panels properly, and as a result they do not perform effectively for very long and they end up obstructing the roadway because of unwanted displacements.
The invention seeks to remedy these drawbacks by proposing equipment which is adapted firstly to installing a road sign whose stability is ensured in a manner which is both effective and permanent by simple means that are often available on site, and secondly to enabling road signs to be stored and transported in a reduced volume.